The present invention is directed to machines, and, in particular, to disabling a machine having or located in an enclosure when a portion of the enclosure is opened.
Technological advances have led to changes in the design of automobiles. For example, hybrid vehicles that include both a standard internal combustion engine (ICE) and an electric motor are now available. These vehicles typically have improved fuel economy as compared to a vehicle including only an ICE.
Hybrid vehicles require electrical power at levels that far exceed the 12 to 24 volts at which ICE's operate in order to drive the electric motor. The motors can use batteries, ultracapacitors, fuel cells, or other sources to power the electric motor that drives the vehicle in some operating conditions. The voltage from these power sources are typically stepped up to a higher voltage and then provided to the motor. Transversely, when braking, the high voltage from the motor is stepped down and used to recharge the power sources.
The elements involved in stepping the power up and down (as well as other devices) are typically located in a protective enclosure. The elements in the protective enclosure are referred to herein as “electrical elements” or “high voltage elements.” The enclosure keeps the electrical elements safe and prevents individuals from harming themselves by touching them. Such enclosures shall be referred to herein as “high voltage enclosures.” At times, a person may need to access electrical elements within the high voltage enclosure for service. In order to make such access safe and to reduce or remove the possibility of an electrical shock, the high voltage enclosure typically includes a mechanical switch that cuts the power supply to the electrical elements when an access cover of the enclosure is removed. The switches are typically connected to a high voltage interlock loop. That is, the power cannot be returned to the electrical elements until the switch is activated (opened or closed depending on orientation). In practice, the access cover is typically formed of metal to provide electromagnetic or radiofrequency shielding and includes a tab or other implement to activate the switch.